1. Field of the Invention
The present invention relates to a light-sensitive printing plate.
2. Description of the Prior Art
Hitherto, when a light-sensitive printing plate is exposed through an original image, the original image is brought into completely intimate contact with the surface of a light-sensitive layer of the light-sensitive printing plate or, when a resin layer is provided on the light-sensitive layer, the surface of the resin layer (hereinafter referred to merely as the surface of the light-sensitive printing plate), by a method in which the light-sensitive printing plate and the original image superposed thereon have been placed between a rubber sheet and a press glass, and a vacuum is produced in the clearance between the rubber sheet and the press glass (hereinafter, this method is referred to as vacuum contact method). Since hitherto used light-sensitive printing layers have a smooth surface, when the original image is contacted with the light-sensitive printing layer using the vacuum contact method, the contact begins from the periphery. Thus, contact at the center portion is prevented, and an extremely long period of time is required for completely contacting the original image with the entire surface of the light-sensitive printing plate. When an imagewise exposure is applied while the contact is incomplete, a clear image can not be obtained at the portion where the contact is incomplete, and thus a sharp point can not be obtained. The long period of time required for the contact reduces the efficiency of the print-making operation, and thus a reduction in time has been desired for a long time.
As a result of investigating the reduction in the time required for bringing the original image in contact with the light-sensitive printing plate by the vacuum contact method, it has been surprisingly found that the time is markedly reduced by providing on the surface of the light-sensitive printing plate a matt layer which is removable at development.